1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to an LCD device having a simplified printed circuit board (PCB).
2. Discussion of the Related Art
LCD devices display an image by controlling the light transmittance of liquid crystal cells in accordance with a video signal. Referring to FIG. 1, an active matrix type LCD device is illustrated. In such an active matrix type LCD device, data voltages, which are supplied to liquid crystal cells Clc, are switched by thin film transistors (TFTs) formed in respective liquid crystal cells Clc, for active control of data to achieve an enhancement in the display quality of a moving image. In FIG. 1, the reference character “Cst” designates a storage capacitor to maintain the data voltage charged in the associated liquid crystal cell Clc, the reference character “DL” designates a data line supplied with the data voltage, and the reference character “GL” designates a gate line supplied with a scan voltage.
For LCD devices, medium and large-size models as well as small-size models are being developed, in pace with the recent development of televisions and monitors with a large screen size. As shown in FIG. 2, such an LCD device includes a control PCB 20, a source PCB 22, a cable 21 connected between the source PCB 22 and the control PCB 20, and a plurality of source chip-on-films (COFs) 24 connected to the source PCB 22 and an LCD panel 25.
Each source COF 24 is electrically coupled to data pads of the source PCB 22 and LCD panel 25. A data integrated circuit (IC) 23 is mounted on each source COF 24.
Signal wirings are formed on the source PCB 22, to transfer digital video data and timing control signals from the control PCB 20.
A control circuit, a dater transfer circuit, etc. are mounted on the control PCB 20. The control PCB 20 supplies data to the data ICs 23, and supplies timing control signals to control operations of the data ICs 23 to the source PCB 22 via the cable 21.
As the LCD panel 25 has an increased size in the LCD device as shown in FIG. 2, the number of data lines and the number of source COFs 24 are correspondingly increased. As a result, the size of the source PCB 22 increases. In this case, there is a difficulty in aligning the source COFs 24 with the source PCB 22. Furthermore, the source PCB 22, which has an increased size as mentioned above, cannot be handled by existing automatic mounting equipment such as surface mount technology (SMT) equipment because the equipment is designed for a source PCB having a size smaller than the large-size source PCB 22. In addition, as the LCD device has an increased size, the number of circuit devices such as memories increases, and the number of output pins increases. For this reason, there is a problem of an increase in the manufacturing costs of the control PCB 20.